Bump content/specs from 8c28a72 to 4639301 (#710)

Bumps [content/specs](https://github.com/scientific-python/specs) from `8c28a72` to `4639301`.
- [Commits](scientific-python/specs@8c28a72...4639301)

---
updated-dependencies:
- dependency-name: content/specs
  dependency-type: direct:production
...

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